Our case study confirms two previous studies demonstrating that a ‘lost’ language can be recovered by hypnosis. These results point to the existence of another type of attrition. Here a distinction is made between this type of attrition of a ‘hidden language’ (HL), that is, one that has not been forgotten but rather has become inaccessible to the speaker, and the traditionally studied attrition of a ‘forgotten language’ (FL). A conflict hypothesis is proposed to explain HL attrition. An attempt is made to show how these two types of attrition could be distinguished and to explain why brain imagery analyses are important for this distinction.